The invention relates to a method of forming to the wall of a pipe a branching for receiving a fluid-carrying component, the method comprising processing into the pipe wall a cylindrical opening having a smaller diameter than the pipe, thereafter fastening the component to the pipe at the opening such that the pipe and the component are in fluid communication, the method comprising arranging around the pipe a tube-clamp-like joint comprising a first part and a second part, which can be tightened against the first part by means of tightening means and which comprises a conduit and a bushing part and a narrower first portion and a broader second portion, and the narrower portion is inserted in the hole, and the second part it tightened against the pipe wall and the component can be fastened in the conduit.
The invention also relates to a junction in a pipe for connecting the pipe into fluid communication with a fluid-carrying component, the junction comprising an opening provided in the wall of the pipe and a connecting part between the pipe and the component, the connecting part comprising a tube-clamp-like joint comprising a first part and a second part, which can be tightened against the first part by means of tightening means and which comprises a bushing part and a narrower first portion and a broader second portion, whereby the narrower portion is positioned in the opening and is surrounded by the walls of the hole and the broader portion is positioned outside the pipe, the narrower portion comprises a first projected surface which is smaller than a second projected surface in the broader portion of the second part, the projected surfaces being directed away from one another, the first projected surface being arranged to exert a first force directed at the narrower portion during fluid pressure in the pipe the first force tending to push away the narrower portion from the hole and the second projected surface being arranged to exert a force directed at the broader portion during the same fluid pressure, this force tending to push the narrower portion towards the pipe in such a manner that a force acts so as to wedge the narrower portion into the hole.
Fluid communication refers herein to the ability of fluid to stream in the junction.
The invention is particularly well applicable to metal pipes, although other pipe materials are also feasible.
There are many ways of connecting a fluid-carrying component, e.g. a pipe or a pipe part, to the wall of another pipe. A common way is to use in the junction a T coupling implemented by a tee. However, a T coupling suffers from drawbacks. One drawback is that the junction is time-consuming, because the pipe has to be cut off to the right length to allow room for the tee, and the tee then has to be connected in a fluid-tight manner at the three free ends thereof. If the junction is implemented by welding, which is often the case in high pressure pipes, the junction requires extensive welding, which may impair the characteristics of the pipe material, even though heat treatment optionally follows the welding. Another drawback in the use of a T coupling is that the tee may be, in spite of a relatively small pipe dimension of 38 mm, for example, extremely costly, particularly in high pressure applications.
When a spray head or a sprinkler operated by a pressure exceeding 16 bar, e.g. 25 to 300 bar, is to be connected to a pipe, the junction is costly to implement by known methods and known components, because especially high safety and tightness requirements are made on a highly loaded junction.
It is known through GB 2 254 119 and GB 2 125 920, for example, to connect components to a pipe by processing an opening into the wall of the pipe. Junctions implemented in this way are tightened by means of elastic seals. Elastic seals are always complicated in high pressure applications, because they easily yield to pressure, easily causing leakage. In the known construction according to GB 2 125 920, a tongue 18 remains in a certain portion and prevents fluid from flowing freely to and from the pipe. The higher the pressure of the fluid in the pipe, the stronger is the resistance provided by the tongue.
For the purpose of eliminating the above drawbacks, the method of the invention is characterized by
processing a cylindrical hole having a diameter smaller than the diameter of the pipe, the hole forming said opening, thereupon
tightening the second part, so that its narrower portion plastically deforms the walls of the hole so that these walls encircle the narrower portion fluid tight.
According to a preferred embodiment, which is especially suitable for high pressure connections, fluid is introduced into the pipe under high pressure which acts on a first projected surface and a second projected surface that is larger than the first projected surface, the pressure on the first surface producing a first force that tends to push away the narrower portion from the hole and the pressure on the second surface producing another force whose direction is opposite to the first force and which is stronger than the first force and which pushes the narrower portion into the hole for deformation of the walls of the hole. The use of a high pressure, e.g. 100 to 300 bar, results in a very firm connection. A lower pressure in excess of 16 bar, which is typically acting when the pipe is in use, keeps the junction tight. Thus a pressure in the pipe tends to close or seal, not open, the junction.
The preferred embodiments of the method of the invention are disclosed in the attached claims 2 to 5.
The junction of the invention is characterized in that the walls of the hole are plastically deformed, and encircle the narrower portion fluid tight. The construction is particularly suitable for high pressure applications. The use of an insert which is small in relation to the tube clamp and provided with a conical surface for resting against the edge of the hole results in an economic solution allowing the connection of different components to the pipe. Such an insert is easy to make in comparison to a solution in which the whole of the second part of the joint would be produced as an uniform, integrated part. An integrated part would be very difficult, if not impossible to make by machining, and would consequently have to be cast.
The major advantages of the method of the invention are that the branching can be produced simply, rapidly and economically without elastic seals and that the result is a branching which tightly and reliably connects the fluid-carrying component in spite of application of high pressure.
The major advantages of the junction are that it is tight even when high pressure is applied, that it is reliable and can be produced economically.